Electromagnetic Compatibility Research Articles

Facile fabrication of biomass chitosan-derived magnetic carbon aerogels as multifunctional and high-efficiency electromagnetic wave absorption materials

Biomass chitosan-derived porous carbon-based materials take the advantage of light weight, adjustable intrinsic conductivity, and environmental friendliness, attracting more attention in the field of electromagnetic compatibility. However, exploring a facile fabrication method to achieve rational structure design and electrical-magnetic coupling for electromagnetic absorption performance enhancement still remains challenging. Here, a unique honeycomb-like porous cobalt/carbon aerogel is fabricated through the directional freezing-drying and carbonization process, and abundant and even-distributed cobalt particles in-situ grow on the carbon skeletons. The aerogel exhibits an impressive electromagnetic wave absorption performance of a −75.8-dB absorption intensity and a −256.9-dB mm−1 specific reflection loss at a low filling content (10%), as well as an 8.53-GHz effective absorption bandwidth. Besides, the aerogel also demonstrates classy radar stealth and thermal insulation performance. The eco-friendly, easily fabricated, and high-performance cobalt/carbon aerogel suggests broad application prospects for electromagnetic compatibility and protection, thermal management, and multifarious electron devices.

Target Detection Method Based on Adaptive Step-Size SAMP Combining Off-Grid Correction for Coherent Frequency-Agile Radar

Coherent frequency-agile radar (FAR) has a low probability of intercept (LPI) and excellent performance of electronic counter-countermeasures (ECCM) and electromagnetic compatibility, which can improve radar cooperation and survivability in complex electromagnetic environments. However, due to the nonlinearity of radar carrier frequency and the limitation of the Doppler tolerance of high-resolution range cells, the undesirable blind-speed sidelobes are generated in the two-dimensional (2D) range–velocity plane after coherent integration (CI) using the traditional methods based on a matching filter, which may degrade the target detection performance. To solve this problem, an adaptive step-size sparsity adaptive matching pursuit (SAMP) algorithm combining off-grid correction (ASSAMP-OC) is proposed in this paper, which seeks to achieve a better trade-off between recovery efficiency and detection performance. Firstly, an adaptive iteration step size based on the Spearman correlation coefficients (SCCS) is devised, which solves the problem of the traditional SAMP algorithm being insensitive to the change in iteration step size when the residuals vary slightly, and improves the recovery speed. Secondly, the off-grid correction method by combining a regularized stagewise backtracking idea and gradient descent optimization (GDO) is adopted to improve the recovery accuracy and suppress the blind-speed sidelobe energy (BSSE), which helps to reduce CI gain loss and improve the target detection performance without the prior information of the sparsity lever. Finally, simulation and experimental results demonstrate the effectiveness and efficiency of the proposed method in terms of target detection probability, target signal energy ratio after recovery, and computational cost, compared to several existing methods.

Research progress of the electromagnetic shielding material of metal fiber: issues and future scope

With the widespread adoption of electronic technology, electromagnetic (EM) interference has become increasingly severe, adversely affecting the normal operation of electronic systems and posing significant threats to human health. EM shielding materials can effectively suppress various EM waves and EM interference generated through space by improving the EM compatibility of electronic systems and electronic devices. Recently, fiber-structure materials have been widely used for EM shielding due to their softness, thinness, and superior shielding efficiency. Therefore, this paper focused on fiber-based EM shielding materials, discussed the basic principles of EM shielding, the types of EM shielding fibers, the efficiency factors of EM shielding fabrics, and presented prospects for the future development of such materials.

A Compact Planar Ultra-Wideband Array Antenna

Ultra-wideband (UWB) antennas have recently gained prominence in communication, radar technology, and electronic warfare domains. The quick development of these antennas is due to the wide bandwidth requirements of pulse radar, ground penetrating radar, electromagnetic compatibility, spaceborne communication systems, stealth target detection, and more. Aiming to address the defects of existing UWB antennas, which often have narrow bandwidth and low gain, a planar ultra-wideband microstrip array antenna was designed to achieve good ultra-wideband characteristics and effectively improve the gain of the antenna. The initial bandwidth of the rectangular monopole antenna was 10 GHz–20 GHz. After loading multiple steps on the monopole patch, the bandwidth was increased to between 10 and 38 GHz. Using the new ultra-wideband array method that combines series feed and angle feed and the defective ground structure (DGS), the array maintains the ultrawide bandwidth span of 10–38 GHz of the array element, and the maximum gain of the antenna in the bandwidth was increased from 5.18 dBi to 9.55 dBi. The challenge of impedance matching of antenna units in ultra-wideband is resolved by the novel array technique, which also increases the antenna’s gain within the bandwidth. The antenna simulation is consistent with the measurement results. With its extensive operating frequency band, high gain, compactness, and favorable radiation attributes, this newly designed antenna holds significant promise for application in UWB radar systems.

Construction and Analysis of the EMC Evaluation Model for Vehicular Communication Systems Based on Digital Maps

With the development of vehicular communication technology, the electromagnetic compatibility requirements of vehicular communication systems are becoming more demanding. The traditional four-level electromagnetic compatibility evaluation model is widely applied in many scenarios. However, this model neglects the mutual interference of electronic devices inside a vehicle, and it cannot evaluate whether reduced radio receiver sensitivity, antenna isolation, and communication distance satisfy the system requirements for vehicular communication, thus making it unsuitable for digital communication systems. With the development of remote sensing technology, high-precision digital maps are easy to acquire and thus widely used. In this work, a modified five-level evaluation model based on digital maps is proposed, where digital maps are employed to support receiver sensitivity, antenna isolation, and communication performance evaluation. Through remote sensing technology and digital maps, a terrain profile is obtained, and a more accurate vehicle communication propagation model is established. In the experiment, an actual armored vehicular communication system example is applied to verify the performance of the proposed five-level evaluation model. Compared with the free-space propagation model, the error of the actual power received by the receiver is reduced by 0.97%, and the error of the communication distance where the sensitivity of the receiver is reduced by more than the system EMC threshold is reduced by 16.78%. The calculated antenna isolation degree is basically consistent with the actual measurement data. The model is able to evaluate the electromagnetic compatibility of an armored vehicular communication system more quickly, accurately, and comprehensively compared to previous evaluation models.

Sliding Mode Control of Buck DC–DC Converter with LC Input Filter

The employment of input filters in modern DC–DC converters is mandatory in order to ensure EMC (Electro-Magnetic Compatibility), provide power electronics with decent voltage and minimize the converter influence on the power grid. The LC type input filters bring also a possibility of voltage and current oscillation that may occur in the system. This oscillation may rise to a certain level that affects system stability. A wide range of methods are employed in order to attenuate these oscillations and allow appropriate system transient response. In this paper, the sliding mode control (SMC) strategy is proposed to reduce the input LC filter voltage and current oscillation and allow DC (Direct Current) output voltage control for both resistive and constant power load. The proposed control algorithm is intended for use in railway, tram and trolleybus DC/DC converters. For the proposed scheme of control simulation, a model is developed using Simulink software. Furthermore, laboratory stand experiments are carried out to verify simulation results.

Nanocomposites Based on Polyethylene and Nickel Ferrite: Preparation, Characterization, and Properties.

Composite materials based on NiFe2O4 nanoparticles and polyethylene matrix have been synthesized by thermal decomposition to expand the application area of high-pressure polyethylene by filling it with nanoscale particles. The synthesized compositions were obtained in the form of a dark gray powder and compressed for further study According to TEM, the average particle size in composites was 2, 3, and 4 nm in samples with a filling of 10%, 20% and 30%. The concentration dependences of the specific electrical resistivity ρV, dielectric permittivity ε, saturation magnetization MS and the parameters of reflection and attenuation of microwave power of the obtained composites were investigated. The threshold for percolation in such materials is found to be within a concentration range of 20…30%. The electronic and atomic structure of composites was studied by methods of Mössbauer spectroscopy, X-ray diffraction and X-ray absorption spectroscopy. The closest atomic environment of nickel and iron in nanoparticles is close to that of crystalline NiFe2O4. The dependence of the nanoparticles size as well as the dependence of the number of tetrahedral or octahedral iron positions in nickel ferrite nanoparticles to their content in polyethylene matrix is established. It is shown that composite materials based on NiFe2O4 nanoparticles and polyethylene matrix can be used as components of electromagnetic compatibility systems.

Analysis and Verification of Airborne Instrument Electromagnetic Emission Test

Electromagnetic compatibility is an important factor affecting aircraft performance and safety. With the increase in the number and type of airborne electronic equipment, the requirements for electromagnetic compatibility (EMC) of airborne equipment are increasingly high [1]. Taking airborne equipment as an example, this paper introduces in detail the problem locating method and rectification method of GJB151A standard CE102 and RE102 test exceeding the standard. It analyzes and summarizes the improper design and installation of EMI filters leading to tests exceeding the standard and gives the interference suppression method. Finally, the correctness of the method is verified by the EMC test.

Functional additive manufacturing of large-size metastructure with efficient electromagnetic absorption and mechanical adaptation

Broadband microwave absorption as a hot research topic plays important roles on electromagnetic compatibility, electromagnetic radiation protection and radar detection disguise. However, traditional molding method is difficult to fabricate large-size curving structures for broadband microwave absorption. Herein, the material extrusion with high-speed printing process was effective to manufacture large-size metastructures for broadband microwave absorption. The polylactic acid was mixed and extruded with nano pyrolytic carbon in high temperature to manufacture functional filaments with high dielectric loss. The printed metastructure integrated with 0.5 mm quartz fiber reinforced composite (QFRC) achieved -10 dB broadband microwave absorption in 3.03-18 GHz and effective load bearing performance in tensile and flexural tests. Severe impedance mismatch brought by QFRC was overcome by appropriate structure design and high-speed printing technique. The proposed design-manufacturing closed loop is a promising approach to fabricate aircraft skin with broadband microwave absorption performance and suitable aerodynamic properties for heavy unmanned aerial drones.

Improved field uniformity in EMC chamber for 6G communication

<span>This paper shows electromagnetic field uniformity in an electromagnetic compatibility (EMC) chamber that is used as a test facility for measuring electromagnetic interference and radiated immunity of 6G communication systems. While not defined yet, 6G radio frequency will work in the wavelength ranges above 95 GHz. With this reason, this paper designed a schroeder-type quadratic residue diffuser for 95 GHz to generate a uniform electromagnetic field in the EMC chamber and studied the field uniformity characteristics in it. To analyze the distribution of electromagnetic fields inside the EMC chamber, finite-difference time-domain (FDTD) numerical analysis method is used. The simulation results show that the EMC chamber with this diffuser satisfies the requirements of international standards and has improved the field uniformity in the chamber.</span>

Study of the energy parameters of the system “solar panels – solar inverter – electric network”

The article presents the results of research into the process of transferring electrical energy from solar panels through a hybrid solar inverter to a three-phase electrical network. An automatic regulation system is presented, which provides power regulation and operation in the mode of maximum power selection from solar panels. The results of the study of the energy efficiency of the system, the parameters of electromagnetic compatibility and the emission of higher harmonic currents are presented.

Analysis Of Power Quality Parameters and Devices for Their Measurement

Purpose. The main objective of this study is to assess the phenomena that affect the parameters of power quality, to consider ways to counteract the deterioration of power quality, to assess the effect of electromagnetic interference on the human body, and to review the available devices for measuring the parameters of electric energy. Methodology. To obtain relevant data, the authors conducted a literature review on the topic of the work using full-text and abstract databases. The main causes of electromagnetic compatibility (EMC) violations and ways to counteract these violations are considered. The main parameters of electricity quality, conditions for their measurement and permissible ranges according to the State Standards of Ukraine (SSU) are highlighted. A review of devices for measuring the parameters of electricity quality and the search for a suitable one that meets Ukrainian standards was carried out. Findings. The authors have proved: 1) the problem of measuring electricity quality parameters is relevant and important for its accurate accounting; 2) control of electricity quality parameters and compliance with state standards allows avoiding negative impact on the electricity supply system; 3) the use of modern digital measuring devices provides greater measurement accuracy than analog ones, and they are able to take into account more parameters in one measurement. Originality. The authors conducted a study in the field of electromagnetic compatibility in the field of electromagnetic compatibility using a digital device that gives more accurate and reliable results of power quality parameters. Practical value. Based on the results obtained, it is possible both to correct the personal research of individual scientists or teams of scientists and to predict further prospects for the development of the subject area «Electromagnetic Compatibility» in traction power supply systems in railway transport. The research can also be useful in the study of the disciplines «Electromagnetic Compatibility of Railway Automation Systems» and «Electrical Circuits and Lines of Railway Automation», organization of scientific and practical seminars, advanced training courses, etc.

Активно-пасивний імпульсно-шумовий радар діапазону 3мм та результати його попередніх випробувань

The subject of this manuscript is broadband noise signals and systems. The aim of this research is to show the results of a modern active-passive 3-mm waveband system consisting of a noise-pulsed radar and a radiometer. Noise radar systems (NRS) based on broadband signals are characterized by high resolution, accuracy, and information content when performing unambiguous measurements of the range and speed of targets, as well as increased electromagnetic compatibility and noise immunity. These distinctive features of NRS determine the relevance of their construction for practical tasks of short- and medium-range radar. Additional opportunities for ensuring secrecy, reliability of detection of objects, and their tracking are provided by the combination of active and passive location modes in conjunction with advancement to the short-wave part of the millimeter (MM) wave band (WB). The most important characteristic of any pulsed radar, which largely determines its potential for practical application, is the operating frequency, as well as the shape and width of the probing signal spectrum. The main idea of this work is to describe the construction scheme and the results of preliminary tests of the developed active-passive system in the 94 GHz band with a noisy 20–100 ns illumination pulse in the 5 GHz band. The obtained values of the energy potential of the system in the active location mode (-105 dB) and the achieved radiometer sensitivities in the passive mode (0.007K and 0.03K) make it possible to observe ground and air objects at a distance of several kilometres. Noted that the measured parameters of the radar, in the case of processing the received signal by pulse compression methods, make it possible to count on ensuring the resolution of targets in range at the level of 10-15 cm. A multiple (more than an order of magnitude) decrease in the interference fluctuations of the received signal, which is due to the facet nature of the backscattering of targets, has experimentally demonstrated using a noise probing pulse compared to a single-frequency pulse. The methods for further work on the development and practical application of the constructed measuring system are outlined.

Retracted: On-Load Electromagnetic Compatibility Test and Simulation Closed-Loop of the Electric Drive System of New Energy Vehicles

Retracted: On-Load Electromagnetic Compatibility Test and Simulation Closed-Loop of the Electric Drive System of New Energy Vehicles

Adaptive multi-modes absorption with enhanced electromagnetic environment compatibility

Absorption of electromagnetic (EM) wave has been widely studied and applied in EM, optics, and material research. By constructing an adaptive multi-mode absorption, an EM absorber approach that can be used in a variety of EM environments is provided in this research. This property demonstrates the absorber has an improved environment compatibility. It is used as an application example to address the issue that has recently come up in phased array research on the need to reduce the coupling between antenna elements in varied beam-scanning cases. After analyzing the electric and magnetic characteristics of a patch antenna array in different beam-scanning states, an absorber structure is constructed, with electric absorption in the sum beam case, magnetic absorption in the difference beam case, and combined electric-magnetic absorption in other beam scanning cases. The proposed method is systematically investigated and, finally validated by simulation and measurement evidently. In arbitrary beam-scanning states, the absorber exhibits good absorption and coupling reduction performance, while the radiation performance of the array is well maintained after introducing the absorber. This research can be used in absorber and coupling reduction studies, as well as, potentially in metamaterial and electromagnetic compatibility (EMC).

A bipolar junction transistor EMC modeling method based on physical characteristic measurement and simplex optimization

A bipolar junction transistor EMC modeling method based on physical characteristic measurement and simplex optimization

Impact of Sc3+/In3+ ions co-substitution on structural, magnetic, and microwave features of SrFe12O19 hexaferrites

ScIn→Sr NHFs have been synthesized via the sol-gel combustion method. The phase and morphonology were analyzed via XRD, SEM, TEM, and HR-TEM. XRD measurements confirmed the purity of all products having the crystallite size (DXRD) of 31–77 nm obtained via Rietveld refinement. The agglomeration of products was observed in SEM and HR-TEM images due to their magnetic character. SEM images revealed the hexagonal-shaped nanoparticles. Mössbauer spectra showed that In3+ and Sc3+ ions are located at generally octahedral (Oh) 4 f2 site. The electron density s of iron ions of 4 f2 and 2a sublattices is affected by doping content. The obtained M-H curves (field-dependence of magnetization) demonstrated ferrimagnetic hysteresis loops at both 300 and 10 K. The analysis of M-H curves also showed that the saturation magnetization (Ms) first declined until x = 0.03, then grew up to x = 0.05, and returned to decrease thereafter. The coercivity (Hc) decreased sharply with Sc-In substitution, transforming the magnetic character of samples from hard to soft. Microwave (MW) properties were measured and analyzed between 33 and 50 GHz. It was demonstrated that the increase of the Sc3+/In3+ concentration led to modifications in amplitude-frequency characteristics of the electromagnetic absorption process. It was shown that Sc3+/In3+ substituted Sr NHFs can be used for developing radioelectronic coatings and providing electromagnetic compatibility.

Designing onboard cable networks components considering the manufacturability requirements

The design of the onboard cable network components of an aircraft that meet the requirements of regulatory and technical documentation is considered. The stages of the life cycle of the aircraft are noted, at which the analysis and evaluation of the technical solutions adopted at the design stage of the aircraft, aimed at adaptability to the installation and dismantling of products and components of the aircraft, take place. The scope of the design documentation required for the manufacture of onboard cable network components is determined. The peculiarity of the design stages and the inconsistency of the requirements of the regulatory and technical documentation used in designing onboard cable network components of the aircraft are indicated. A set of requirements for manufacturability, efficiency, reliability and electromagnetic compatibility of onboard cable network components is formalized. The criteria for the harness manufacturability are determined. A method is proposed for synthesizing the image of the onboard cable network components using a graph which vertices are supplemented with attributes that characterize the features of a wired connection to the elements of onboard systems. An algorithm of the designer's actions is developed when determining the need to introduce a connector into an electrical circuit, taking into account the requirements of the electromagnetic compatibility of wires. Recommendations for designers of aircraft onboard cable network components are formulated.

An Ultrathin Polarization Free Asterick-Shaped Metamaterial Absorber with Quad-Band Characteristics

In this paper, a quad-band absorber is proposed and developed, which is exhibiting ultrathin and polarization insensitive behaviour. It has been designed to be operated in S, C, and Ku bands with absorptions peaks at more than 95%. The proposed absorber is implemented on a FR4 glass epoxy laminate with an equivalent electrical thickness of 0.0108 λ0, where λ0 is the wavelength corresponding to the lowest frequency of operation. This confirms the ultrathin nature of the structure. The absorption performance of the proposed structure has been characterized under normal and oblique incidences followed by their experimental verification. Presented results demonstrate highly polarization-independent behavior of the proposed absorber due to its symmetric geometry. Also, the electromagnetic field distributions have been studied to acquire better insight of the absorption mechanism corresponding to distinct elements present in the structure. It is characterized in terms of its behavior as metamaterial, which ensures the miniaturization. The proposed absorber is suitable to be used in applications like radar cross section reduction, stealth technology, radio frequency identification, and electromagnetic compatibility.

Propellant Influence on Electromagnetic Environment Generated by Stationary Plasma Thrusters

Possible aspects of violation of the functional safety of spacecraft in terms of electromagnetic compatibility with electric rocket thrusters in their work on alternative working substances are considered. The procedure of experimental determination of spectral–time characteristics of own electromagnetic radiation of laboratory model of stationary plasma thruster SPT-70 developed by the Research Institute of Applied Mechanics and Electrodynamics of the Moscow Aviation Institute is described. Measurements of noise emissions were carried out on a vacuum installation with a “radiotransparent” compartment and a shielded echo-free camera in the frequency range of 1–12 GHz for typical discharge capacities (600, 800, and 1000 W), vertical and horizontal polarization, and various working substances used (krypton and xenon). The conducted studies have allowed obtaining new comparative results of the assessment of spectral characteristics of SPT-70 radiation for standard modes and prospective working bodies within the orthogonal polarization bases. The new results should include information about the radiation characteristics of SPT-70 in the time area. It is shown that the transition from xenon to krypton retains the pulsed nature of the radiation of a stationary plasma thruster, leading not only to an increase in the amplitude of pulses, but also to an increase in the frequency of repetition of “bursts” and an increase in their duration, which requires additional measures to ensure electromagnetic compatibility in order to preserve the functional safety of the spacecraft.